In the commercial software world, user interfaces are generally designed by one group. Like Microsoft for Windows or Apple for Mac OS. Those desktop environments were designed by one company who did things like user testing and statistical analysis to try and make the desktop they thought would work best. Linux is different. Large groups definitely DO perform user testing and statistical analysis, but one group can also say "Here's what we want" and, if they have the ability to code it, their idea comes into being. It's pretty amazing, when you think about it. Linux lets people create what they want. If you don't like what's out there, fork it! Or start from scratch! You're in control!

Most commercial GUIs are driven more by the need to produce something new for the next sales cycle than by actual improvements. If Microsoft gives the next version of Windows the same interface as the last, they have no claim to get you to upgrade... nor would many users, who only see the GUI, see any reason to upgrade.

Linux world has its own problems but at least it's not driven by upgrades for the sake of sales. It's unfortunate though, that the de facto leader of the Linux camp, Ubuntu, tries to compete with MS using the same philosophy of worthless GUI upgrades.